Merge pull request #529 from edx/grady/rubric-validation-event-handler

Validation and Dynamic Updates of Training Examples
Fixes the Bleed through of the Submission box Resize Handle by increasing the Z score of the modal which it was bleeding through.
Merge branch 'authoring' of https://github.com/edx/edx-ora2 into grady/fix-resize-bleed-through

Conflicts:
	openassessment/xblock/static/css/openassessment.css
Merge pull request #533 from edx/grady/fix-resize-bleed-through

Grady/fix resize bleed through